| 1. |
- Akhter, Shahida, et al.
(författare)
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Glassy behavior of diluted Cu-Zn ferrites
- 2018
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Ingår i: Journal of Magnetism and Magnetic Materials. - : ELSEVIER SCIENCE BV. - 0304-8853 .- 1873-4766. ; 452, s. 261-265
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Tidskriftsartikel (refereegranskat)abstract
- The magnetic behavior of Zn substituted Cu-Zn spinel ferrites having chemical formula Cu1-xZnxFe2O4 (x = 0.7, 0.8, 0.9 and 1.0) has been studied by SQUID magnetometry, by means of magnetic hysteresis, field-cooled (FC) and zero-field-cooled (ZFC) magnetization, memory effect and low field ac susceptibility measurements. These measurements suggest that the ferrimagnetic phase of the x <= 0.8 samples is gradually turned into a spin glass (x >= 0.9). The compound with x = 0.9 exhibits the typical dynamical behavior of spin glasses, with indication of aging, rejuvenation and memory effects. The evolution of the magnetic properties of Cu-Zn spinel ferrites with substitution of Zn for Cu is discussed.
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| 2. |
- Akhter, Shahida, et al.
(författare)
-
Magnetic and magnetocaloric properties of Cu1-xZnxFe2O4 (x=0.6, 0.7, 0.8) ferrites
- 2014
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Ingår i: Journal of Magnetism and Magnetic Materials. - : Elsevier BV. - 0304-8853 .- 1873-4766. ; 367, s. 75-80
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Tidskriftsartikel (refereegranskat)abstract
- The effect of Zn substitution on the magnetic and magnetocaloric properties of Cu1-xZnxFe2O4 (x=0.6, 0.7, 0.8) ferrites over a wide temperature range has been investigated. The polycrystalline samples were synthesized using the solid-state reaction at sintering temperature 1050 degrees C (1323 K) for 2 h and has been characterized by SQUID magnetometry. Magnetization versus temperature showed that all samples exhibit a paramagnetic to ferromagnetic transition with decreasing temperature. The Curie temperature T-c is found to decrease from 373 K for x=0.6 to 140 K for x=0.8 as well as the saturation magnetization Ms which shifts from 100 to 44 emu/gm. The magnetocaloric effect was obtained by measuring a family of M-I1 curves at set temperature intervals and calculating the entropy change, LIS for this system using the Maxwell relation. The AS of all samples increased with increasing applied field and showed a maximum around their respective 'Fe. The entropy change (Delta S) decreased with increasing Zn content, whereas the relative cooling power (RCP) slightly increased. The large RCP and Delta S found in Zn substitution Cu-Zn ferrites will be interesting for magnetic refrigeration near room temperature.
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